Water purification device

Abstract

To provide a water purification device which can obtain sterilization effects of a filtering medium by ozone, reduces wear and damage by cleaning of the filtering medium, and contributes to a longer life of the filtering medium and reduction in replacement frequency.SOLUTION: A water purification device 1 includes a filtration part 10 for removing an object to be treated from water to be treated containing the object to be treated by a filtering medium 19, and generating pure water, a concentration measuring part 20 for measuring the concentration of the object to be treated in the pure water, and a control part 3 for controlling execution of a filtration mode to generate the pure water from the water to be treated and a cleaning mode to clean the filtering medium 19. The control part 3 includes: a storage part 3b for storing a reference value of the concentration of the object to be treated; a comparison part 3c of the object to be treated for comparing the measured concentration of the object to be treated with the reference value; a determination part 3d for determining to be a request cleaning state required for cleaning the filtering medium 19 when the concentration of the object to be treated of the pure water generated in the filtration mode is equal to or more than the reference value; and a cleaning execution part 3f for executing the cleaning mode when it is determined to be the request cleaning state by the determination part 3d.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a water purification device. [Background technology]

[0002] Physical filtration, which uses activated carbon or sand as a filtering material, has been known as a water treatment method for removing impurities from water (see, for example, Patent Document 1). In water purification devices that use filtering material, impurities, especially organic matter, tend to accumulate inside the filtering material, so it is necessary to periodically clean the filtering material and discharge the organic matter to the outside.

[0003] However, organic matter with a small molecular weight is adsorbed into the pores of the filter material, making it difficult to remove even after cleaning. Furthermore, in the case of a home water purifier, if the device is left unattended for an extended period of time, cleaning operations are not performed, resulting in the accumulation of organic matter on the filter material for a long period of time. As the accumulation time increases, the adsorbed and accumulated organic matter becomes a nutrient source, causing bacteria such as Legionella to develop and multiply on the filter material, resulting in human infection, which has become a problem. Decomposition and sterilization methods using ozone are known to decompose organic matter contained in the water to be treated and the treated water, and to sterilize the multiplying bacteria (e.g., Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-75917 [Patent Document 2] Special Publication No. 6-59474 Summary of the Invention [Problem to be solved by the invention]

[0005] The water treatment system disclosed in Patent Document 1 describes an efficient backwashing method for a water purifier that uses activated carbon. As described, backwashing is an effective method for restoring the filter material of a water purifier, but on the other hand, friction during backwashing leads to wear on the filter material, which is one of the factors that shortens the filter material's lifespan.

[0006] Furthermore, the water treatment system disclosed in Patent Document 2 combines an ozone supply device with a water purification device to decompose organic matter and disinfect bacteria. However, it is known that the strong oxidation and decomposition reactions caused by ozone affect not only organic matter but also filtering materials. In particular, in water treatment systems using activated carbon, there is a risk that the filtering material may be damaged by the oxidation and decomposition reactions, leading to a shortened lifespan of the filtering material.

[0007] Therefore, the present invention is intended to solve the above-mentioned conventional problems, and aims to reduce wear and damage caused by cleaning the filter material of a water purification device, thereby contributing to extending the life of the filter material and reducing the frequency of replacement. [Means for solving the problem]

[0008] To achieve this object, the water purifier according to the present invention comprises a filtration unit that generates purified water by removing the substance to be treated from water to be treated that contains the substance to be treated using a filtration material, a concentration measurement unit that measures the concentration of the substance to be treated in the purified water, and a control unit that controls execution of a filtration mode that generates purified water from the water to be treated and a cleaning mode that cleans the filtration material, and the control unit includes a memory unit that stores a reference value for the concentration of the substance to be treated, a comparison unit that compares the measured concentration of the substance to be treated with the reference value, a determination unit that determines that a cleaning-required state requires cleaning of the filtration material when the concentration of the substance to be treated in the purified water generated in the filtration mode is equal to or greater than the reference value, and a control unit that executes the cleaning mode when the determination unit determines that a cleaning-required state exists. and a cleaning execution unit for performing the cleaning, thereby achieving the intended purpose. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a water purifier that reduces wear and damage caused by cleaning of the filter material, thereby contributing to extending the life of the filter material and reducing the frequency of replacement. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a water purifier according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing the configuration of the control unit according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a flowchart showing the operation of the water purifier according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram of the filtration mode according to the first embodiment of the present invention. [Figure 5] FIG. 5 is a schematic diagram of the untreated water washing mode according to the first embodiment of the present invention. [Figure 6] FIG. 6 is a schematic diagram of the ozone water cleaning mode according to the first embodiment of the present invention. [Figure 7] FIG. 7 is a block diagram showing the configuration of a water purifier according to the second embodiment of the present invention. [Figure 8] FIG. 8 is a flowchart showing the operation of the water purifier according to the second embodiment of the present invention. [Figure 9] FIG. 9 is a flowchart showing the operation of the water purifier according to the third embodiment of the present invention. [Figure 10] FIG. 10 is a flowchart showing the operation of the water purifier according to the third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are examples of specific embodiments of the present invention and are not intended to limit the technical scope of the present invention. Furthermore, each drawing used in the embodiments is a schematic drawing, and the ratios of the sizes and thicknesses of the components in each drawing do not necessarily reflect the actual dimensional ratios.

[0012] (Embodiment 1) ((Overall structure)) A water purifier 1 according to the present embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram of the water purifier 1 according to the present embodiment. Figure 2 is a block diagram showing the configuration of a control unit 3 according to the first embodiment of the present invention.

[0013] The water purifier 1 is a device that purifies water containing impurities such as organic matter and bacteria as the treated material, which is water delivered from a water purification plant or the like via a water supply pipe 2, and makes the water usable for daily use. The water purifier 1 purifies the water and cleans the filter material by executing a filtration mode, a treated water cleaning mode, and an ozone water cleaning mode. Details of each mode will be described later. The treated water cleaning mode and the ozone water cleaning mode are collectively referred to as the cleaning mode. As shown in FIG. 1, the water purifier 1 includes an inlet 21, an ozone generator 7, an ozone water generator 9, a filtration unit 10, a concentration measurement unit 20, a purified water outlet 27, a backwash outlet 29, and a control unit 3.

[0014] Inlet 21 is an opening through which water to be treated, which is pressure-fed from outside water purifier 1, such as a water purification plant, via water pipe 2, is introduced into water purifier 1. Inlet 21 is provided in a housing that constitutes water purifier 1, and is connected in communication with inlet pipe 22, which will be described later.

[0015] The ozone generator 7 is a device that takes in the water to be treated and generates ozone gas by electrolyzing it using electrodes. The ozone generator 7 is connected in communication with the second water supply pipe 23b, which will be described later. An ozone water production section 9 is provided downstream of the ozone generation section 7 .

[0016] The ozonated water generating unit 9 is a device that generates cleaning water (ozonated water) by mixing the water to be treated with ozone gas generated in the ozone generating unit 7. In the ozonated water generating unit 9, instead of the water to be treated, ozone gas can be mixed with purified water generated in the filtration unit 10 described below to generate cleaning water. In this case, a pipe or the like is provided to supply the generated purified water to the ozonated water generating unit 9.

[0017] The filtration unit 10 generates purified water by capturing and separating and removing substances to be treated, such as organic matter or bacteria, contained in the water to be treated using the filtration material 19 provided inside. The filtration unit 10 is connected in communication with the third water supply pipe 23c, the water conveyance pipe 15, the purified water discharge pipe 26, and the backwash discharge pipe 28. Note that purified water is water from which substances to be treated, such as organic matter or bacteria, have been separated and removed.

[0018] A switching valve 11 and a one end opening 13 are provided vertically above the filtration section 10, and a water pipe 15 and a filtration material 19 are provided inside the filtration section 10.

[0019] The switching valve 11 is a valve that switches the destination of the water flowing into the filtration unit 10 and the water discharged from the filtration unit 10 depending on the operating mode of the water purifier 1. The switching valve 11 is connected to each of the third water supply pipe 23c, the one-end opening 13, the water conduit 15, the purified water discharge pipe 26, and the backwash discharge pipe 28. The switching valve 11 is connected to the control unit 3 so as to be able to communicate wirelessly or by wire, and the water destination is switched by a signal from the control unit 3.

[0020] The one-end opening 13 is connected to an end of the third water supply pipe 23c by switching the switching valve 11 in a water-conveying manner in the filtration mode, and is an opening for introducing the water to be treated flowing through the third water supply pipe 23c into the filtration unit 10. Furthermore, the one-end opening 13 is connected to an end of the backwashing discharge pipe 28 by switching the switching valve 11 in a water-conveying manner in the water-to-be-treated cleaning mode and the ozone water cleaning mode, and is an opening for sending the water in the filtration unit 10 to the backwashing discharge pipe 28. The one-end opening 13 corresponds to the other-end opening 17 described below, and is provided vertically above the other-end opening 17.

[0021] The filtration material 19 is a substance that captures substances to be treated, such as organic matter or bacteria, contained in the water to be treated, and can be, for example, activated carbon or filter sand. In this embodiment, both activated carbon and filter sand are used as the filtration material 19. The filtration material 19 is provided below the filtration unit 10, and there is a space above the filtration material 19 within the filtration unit 10. Providing this space improves cleaning efficiency in the cleaning mode.

[0022] The water conduit 15 is provided within the filtration unit 10 and is a pipe that connects the upper and lower parts of the filtration unit 10, with an other-end opening 17 provided at its lower end. In the filtration mode, the water to be treated that has flowed into the filtration unit 10 is conveyed from the upper part to the lower part of the filtration unit 10 through the water conduit 15, and in the water to be treated cleaning mode and the ozone water cleaning mode, the water used to clean the filtration material 19 in the filtration unit 10 is conveyed from the lower part to the upper part of the filtration unit 10 and then sent out of the filtration unit 10.

[0023] The other end opening 17 is buried in the filtering material 19 and is provided vertically below the one end opening 13. The other end opening 17 is an opening that supplies water in the water conduit 15 into the filtration section 10, or supplies water in the filtration section 10 to the water conduit 15.

[0024] The lower part of the water conduit 15, including the opening 17 at the other end, is buried in the filtration material 19, while the upper part is not buried in the filtration material 19 and is connected to the switching valve 11. In other words, the water conduit 15 directs the water conveyed from the switching valve 11 through the filtration material 19 present in the lower part of the filtration unit 10. 9, or supplies water in the filtration section 10 to the switching valve 11 from below the filtration section 10.

[0025] The concentration measurement unit 20 is provided on the path of the purified water discharge pipe 26, which will be described later, and is a device that measures the water quality of the purified water produced by purification in the filtration unit 10. As the concentration measurement unit 20, for example, a COD meter (Chemical Oxygen Demand) can be used.

[0026] The purified water outlet 27 is an opening through which the water to be treated that has been filtered by the water purifier 1 is taken out as purified water (treated water) to the outside of the water purifier 1. The purified water outlet 27 is provided in a housing that constitutes the water purifier 1, and is connected in communication with the purified water outlet pipe 26, which will be described later.

[0027] Backwashing outlet 29 is an opening for discharging the untreated water or cleaning water used to clean filtration section 10 to the outside of water purifier 1. Backwashing outlet 29 is an opening provided in a housing constituting water purifier 1, and is connected in communication with backwashing discharge pipe 28. Note that the cleaning water is water containing ozone gas.

[0028] ((Flow paths and valves)) The flow path of the water purifier 1 is made up of an inlet pipe 22, a first water supply pipe 23a, a second water supply pipe 23b, a third water supply pipe 23c, a purified water discharge pipe 26, and a backwash discharge pipe .

[0029] Inflow pipe 22 is connected in communication with inlet 21 and upstream switching valve 5, and is a pipe that supplies the water to be treated that has been taken into water purifier 1 from inlet 21 to upstream switching valve 5.

[0030] The upstream switching valve 5 is a valve that switches the water destination so that water is supplied from the inlet pipe 22 to either the first water supply pipe 23a or the second water supply pipe 23b. For example, a three-way motor-operated valve can be used as the upstream switching valve 5. The upstream switching valve 5 is connected to the control unit 3 wirelessly or by wire so as to be able to communicate with the control unit 3, and the water destination is switched by a signal from the control unit 3.

[0031] The upstream switching valve 5 is connected to the filtration unit 10 by a first water supply pipe 23a, a second water supply pipe 23b, and a third water supply pipe 23c.

[0032] The first water pipe 23a is a pipe that connects the upstream switching valve 5 to a branch point B, which will be described later, and is used in the filtration mode and the untreated water washing mode.

[0033] The second water supply pipe 23b is a pipe that connects the upstream switching valve 5 to a branch point B described later, and is used in the ozone water cleaning mode. A constant flow valve 24, an ozone generator 7, and an ozone water generator 9 are provided on the second water supply pipe 23b.

[0034] The constant flow valve 24 is a valve that stabilizes the flow rate of the water to be treated, which is fed to the ozone generation unit 7, at a constant flow rate during operation in the ozone water cleaning mode, and is connected in communication with the second water feed pipe 23b.

[0035] The third water pipe 23c is a pipe that connects a branch point B (described later) to one end opening 13 of the filtration unit 10, and is used in the filtration mode, the untreated water cleaning mode, and the ozone water cleaning mode.

[0036] The downstream end of the inlet pipe 22, the upstream end of the first water supply pipe 23a, and the upstream end of the second water supply pipe 23b are connected to each other, and the connection point is a branch point A. An upstream switching valve 5 is provided on the branch point A.

[0037] The downstream end of the first water supply pipe 23a, the downstream end of the second water supply pipe 23b, and the upstream end of the third water supply pipe 23c are connected to each other, and the connection point is a branch point B. A three-way valve 25 is provided on the branch point B.

[0038] The three-way valve 25 is a valve that switches the water supply source so that water is supplied from either the first water supply pipe 23 a or the second water supply pipe 23 b to the third water supply pipe 23 c. The three-way valve 25 is connected to the control unit 3 wirelessly or by wire so as to be able to communicate with the control unit 3, and the water supply destination is switched by a signal from the control unit 3.

[0039] The purified water discharge pipe 26 is connected in communication with the switching valve 11 and the purified water discharge port 27, and is a pipe that conveys the water to be treated, from which organic matter, bacteria, etc. have been removed by the filtration unit 10, to the purified water discharge port 27. A concentration measurement unit 20 is provided on the path of the purified water discharge pipe 26.

[0040] The backwashing discharge pipe 28 is connected in communication with the switching valve 11 and the backwashing discharge port 29, and is a pipe that delivers the untreated water or washing water used to wash the filtration section 10 to the backwashing discharge port 29.

[0041] The control unit 3 controls the switching of the flow path of the water to be treated flowing through the water purifier 1 during each of the filtration mode, the water to be treated cleaning mode, and the ozone water cleaning mode. The specific switching of the flow path by the control unit 3 during each mode will be described later. The control unit 3 can be realized as hardware using elements or mechanical devices such as a computer's central processing unit (CPU), or as software using a computer program. Therefore, these functional blocks can be realized in various forms by combining hardware and software. More specifically, the control unit 3 is connected to each of the ozone generator 7, ozone water generator 9, upstream switching valve 5, constant flow valve 24, three-way valve 25, switching valve 11, and concentration measurement unit 20 via wired or wireless connections and controls the operation of each component. As shown in FIG. 2, the control unit 3 includes a memory unit 3b, a workpiece comparison unit 3c, a determination unit 3d, a counting unit 3e, and a cleaning execution unit 3f.

[0042] The memory unit 3b stores a reference value for the concentration of the target substance. The reference value for the concentration of the target substance can be set with reference to a water quality standard value, etc., appropriate for the target substance. For example, in Japan, the water quality standard value for organic matter is set at 3 mg / L or less for total organic carbon (TOC). If this value is used as the reference value for the concentration of the target substance, purified water that always complies with the water quality standard can be provided. Note that although the reference value is referred to here as a reference value, even if the reference value is expressed as a range, the range can also be considered as the reference value.

[0043] The object to be treated comparison unit 3c compares the object concentration measured by the concentration measurement unit 20 with the reference value of the object concentration stored in the storage unit 3b, and transmits the comparison result to the determination unit 3d.

[0044] The determination unit 3d determines whether or not the purified water generated in the filtration mode is in a state requiring cleaning based on whether the concentration of the target substance in the purified water is equal to or greater than a reference value or less than the reference value. Specifically, the determination unit 3d determines that the purified water is in a state requiring cleaning, in which the filtration medium 19 needs to be cleaned, when the concentration of the target substance in the purified water is equal to or greater than a reference value.

[0045] The number measuring unit 3e measures the number of times that the determining unit 3d has determined that the cleaning-needed state has occurred.

[0046] The cleaning execution unit 3f executes the cleaning mode when it is determined that the cleaning is required based on information from the counting unit 3e. Specifically, the cleaning execution unit 3f executes the untreated water cleaning mode until the cleaning is required a predetermined number of times, and executes the ozone water cleaning mode when the cleaning is required a predetermined number of times.

[0047] The configuration of the water purifier 1 is as described above.

[0048] Next, the operation of the water purifier 1 will be described.

[0049] First, the filtration mode and cleaning mode of the water purifier 1 will be described with reference to Figures 3 and 4. Figure 3 is a flowchart showing the operation of the water purifier 1 according to the first embodiment of the present invention. Figure 4 is a schematic diagram of the water purifier 1 according to the present embodiment in the filtration mode.

[0050] The water purifier 1 operates in a filtration mode in which the water to be treated is filtered, and a cleaning mode in which the filter material 19 is cleaned. The cleaning mode includes a water to be treated cleaning mode in which the water to be treated is sent to the filtration unit 10 in the opposite direction to the raw water sent in the filtration mode, and an ozone water cleaning mode in which ozone water is sent to the filtration unit 10.

[0051] First, as shown in FIG. 3, when the water purifier 1 is activated, the filtration mode begins (step S001). In the filtration mode, the water purifier 1 is controlled by the control unit 3 such that the upstream switching valve 5 connects the inlet pipe 22 to the first water supply pipe 23a, the three-way valve 25 connects the first water supply pipe 23a to the third water supply pipe 23c, and the switching valve 11 connects the third water supply pipe 23c to the one-end opening 13. As a result, as shown by the white arrows in FIG. 4, water to be treated containing impurities flows into the water purifier 1 from the outside and flows through the inlet 21, the inlet pipe 22, the upstream switching valve 5, the first water supply pipe 23a, the three-way valve 25, the third water supply pipe 23c, and the switching valve 11 in this order. In other words, the inlet pipe 22, the first water supply pipe 23a, the third water supply pipe 23c, and the switching valve 11 form a purification flow path, and the water to be treated flows through the purification flow path. The water to be treated that has flowed through switching valve 11 flows into filtration section 10 from one end opening 13 and flows through filtration material 19 provided within filtration section 10. At this time, impurities in the water to be treated are adsorbed by filtration material 19, and the water to be treated is filtered. Purified water produced by filtering the water to be treated flows through purified water discharge pipe 26 and is sent out of water purifier 1 from purified water discharge port 27.

[0052] When the filtration mode is executed, the concentration measurement unit 20 measures the concentration of the target substance in the purified water that has been purified by the filtration unit 10 (step S002). The measured concentration information of the target substance is sent to the target substance comparison unit 3c.

[0053] The object comparison unit 3c compares the object concentration information received from the concentration measurement unit with the reference value of the object concentration stored in the memory unit 3b (step S003). If the comparison result shows that the object concentration is less than the reference value, the filtration mode continues (NO in step S003). On the other hand, if the object concentration is equal to or greater than the reference value (YES in step S003), the determination unit 3d determines that the filtering medium 19 needs to be cleaned (step S004).

[0054] The counting unit 3e counts the number of times that it has been determined that the cleaning is necessary.

[0055] If the number of times that the cleaning-required state is determined to be less than the predetermined number (NO in step S005), the cleaning execution unit 3f ends the filtration mode (step S007a) and executes the untreated water cleaning mode (step S008a). Note that the predetermined number is a real number equal to or greater than 2.

[0056] Here, the operation of the water purifier 1 in the untreated water washing mode will be described with reference to Fig. 5. Fig. 5 is a schematic diagram of the untreated water washing mode according to this embodiment.

[0057] In the water purifier 1, in the treatment water cleaning mode, the control unit 3 controls the upstream switching valve 5 to communicate the inlet pipe 22 with the first water supply pipe 23a, and the three-way valve 25 controls the first water supply pipe 23b. a and third water supply pipe 23c are in communication with each other, and switching valve 11 is in a state where third water supply pipe 23c is in communication with water supply pipe 15. As a result, as shown by the white arrows in FIG. 5 , water to be treated flows into water purifier 1 from the outside and flows through inlet 21, inlet pipe 22, upstream switching valve 5, first water supply pipe 23a, three-way valve 25, third water supply pipe 23c, switching valve 11, and water supply pipe 15 in this order. In other words, inlet pipe 22, first water supply pipe 23a, third water supply pipe 23c, and water supply pipe 15 form a cleaning flow path, and the water to be treated flows through the cleaning flow path. After flowing through water supply pipe 15, the water to be treated flows into filtration unit 10 through opening 17 on the other end of filtration unit 10 and flows through filtration material 19 provided within filtration unit 10. In other words, the water flows into filtration unit 10 from the end opposite to that in filtration mode. The inflowing water to be treated passes through the holes in the filtration material 19 and between the filtration material 19, thereby removing the substances to be treated that are adsorbed in the holes in the filtration material 19 and between the filtration material 19. In this way, the water to be treated that flows in from the lower part of the filtration unit 10 is sent to the upper part of the filtration unit 10 while cleaning the internal filtration material 19, and is sent to the backwashing discharge pipe 28 via the switching valve 11. The water to be treated then flows through the backwashing discharge pipe 28 and is discharged from the backwashing discharge port 29 to the outside of the water purification device 1. Returning to FIG. 3 .

[0058] If the execution time of the raw water cleaning mode is less than a certain time (e.g., 10 minutes) (NO in step S009a), the raw water cleaning mode continues to be executed. On the other hand, if the execution time of the raw water cleaning mode is equal to or longer than the certain time (YES in step S009a), the execution of the cleaning mode ends, and the filtration mode is executed or the system enters a standby state where the execution of the filtration mode is awaited.

[0059] On the other hand, if the number of times that it has been determined that the cleaning state is necessary is equal to or greater than the predetermined number of times (YES in step S005), the number of times that it has been determined that the cleaning state is necessary, which is measured by the number measuring unit 3e, is reset (step S006).Then, the cleaning execution unit 3f ends the filtration mode (step S007b) and executes the ozone water cleaning mode (step S008b).

[0060] Here, the operation of the water purifier 1 in the ozone water cleaning mode will be described with reference to Fig. 6. Fig. 6 is a schematic diagram of the ozone water cleaning mode according to the present embodiment.

[0061] In the water purifier 1, under the control of the control unit 3 in the ozone water cleaning mode, the upstream switching valve 5 connects the inlet pipe 22 to the second water supply pipe 23b, the three-way valve 25 connects the second water supply pipe 23b to the third water supply pipe 23c, and the switching valve 11 connects the third water supply pipe 23c to the water conduit 15. As a result, as shown by the white arrows in Figure 6, the water to be treated flows into the water purifier 1 from the outside, passes through the inlet 21, the inlet pipe 22, the upstream switching valve 5, the second water supply pipe 23b, and the constant flow valve 24, and then flows into the ozone generator 7. The water to be treated that flows into the ozone generator 7 is electrolyzed by a pair of electrodes (anode and cathode) provided inside the ozone generator 7, and ozone gas is generated by this electrolysis. The water to be treated containing the ozone gas flows into the ozone water generator 9, where the ozone gas dissolves in the water to produce cleaning water containing ozone. The cleaning water generated in the ozonated water generator 9 flows through the three-way valve 25, the third water supply pipe 23c, the switching valve 11, and the water conduit 15 in this order. The cleaning water that flows through the water conduit 15 flows into the filtration unit 10 from the other end opening 17 of the filtration unit 10 and flows through the filtration material 19 provided within the filtration unit 10. That is, the cleaning water flows into the filtration unit 10 from the end opposite to the end in the filtration mode. The flowing cleaning water passes through the pores and spaces in the filtration material 19, thereby removing the target substances adsorbed in the pores and spaces in the filtration material 19 and sterilizing the ozone. In this way, the cleaning water that flows into the lower part of the filtration unit 10 cleans the internal filtration material 19 while being conveyed to the upper part of the filtration unit 10 and then conveyed to the backwash discharge pipe 28 via the switching valve 11. The cleaning water then flows through the backwash discharge pipe 28 and is discharged from the backwash discharge outlet 29 to the water purifier 1. Returning to FIG. 3 .

[0062] If the execution time of the ozone water cleaning mode is less than a certain time (for example, 2 minutes) (step S00 If the result of step S009b is NO, the ozone water cleaning mode continues. On the other hand, if the execution time of the ozone water cleaning mode is equal to or longer than the predetermined time (step S009b YES), the execution of the cleaning mode ends, and the filtration mode is executed or the system enters a standby state where the execution of the filtration mode is awaited.

[0063] In this way, the filtration mode, the untreated water cleaning mode, and the ozone water cleaning mode are repeatedly executed in the water purifier 1. In other words, the production of purified water by the filtration unit 10 and the regeneration of the filtration unit 10 are repeatedly executed.

[0064] In addition, when using the water purifier 1 on a daily basis in an ordinary household, the frequency of running the ozone water cleaning mode is about once every few days to once a week, which is effective in suppressing bacterial growth. For example, if it is determined that cleaning is necessary about once a day, the above-described condition can be met by setting the predetermined number of times to 3 to 7 times.

[0065] As described above, the water purifier 1 according to this embodiment can provide the following effects.

[0066] (1) The water purifier 1 includes a filtration unit 10 that removes the target substance from water to be treated using a filtration material 19 to produce purified water, a concentration measurement unit 20 that measures the concentration of the target substance in the purified water, and a control unit 3 that controls the execution of a filtration mode that produces purified water from the water to be treated and a cleaning mode that cleans the filtration material 19. The control unit 3 includes a memory unit 3b that stores a reference value for the target substance concentration, a target substance comparison unit 3c that compares the measured target substance concentration with the reference value, a determination unit 3d that determines that a cleaning-required state exists, in which cleaning of the filtration material 19 is necessary, when the concentration of the target substance in the purified water produced in the filtration mode is equal to or greater than the reference value, and a cleaning execution unit 3f that executes the cleaning mode when the determination unit 3d determines that a cleaning-required state exists.

[0067] With this configuration, the need for cleaning is determined based on the concentration of the substance to be treated contained in the purified water, so the filtration material 19 can be used until it breaks through. Furthermore, because the filtration material 19 is cleaned based on the concentration of the substance to be treated in the purified water, the cleaning frequency of the filtration material 19 can be maintained at an appropriate level. This prevents the contamination of the substance to be treated in the purified water above the standard value due to insufficient cleaning, and also prevents wear on the filtration material 19 due to unnecessary cleaning.

[0068] That is, in the water purifier 1, wear and damage caused by cleaning the filter material can be reduced, which contributes to extending the life of the filter material 19 and reducing the frequency of replacement.

[0069] (2) The water purifier 1 includes an ozone generator 7 that generates ozone gas by electrolysis of water, and an ozone water generator 9 that mixes ozone gas with water to be treated or purified water to generate ozone water. The cleaning mode includes a water to be treated cleaning mode in which water to be treated is sent to the filtration unit 10 in a direction opposite to the direction of raw water sent in the filtration mode, and an ozone water cleaning mode in which ozone water is sent to the filtration unit 10. The control unit 3 also includes a count counter 3e that counts the number of times a cleaning-needed state is determined, and the cleaning execution unit 3f executes the water to be treated cleaning mode until a cleaning-needed state is determined a predetermined number of times, and executes the ozone water cleaning mode when a cleaning-needed state is determined a predetermined number of times.

[0070] Because the action of ozone causes deterioration of the filtration material 19, if ozone water is used every time the treated water cleaning mode is performed, there is a possibility that the lifespan of the filtration material 19 will be rapidly shortened. However, with the above configuration, the ozone water cleaning mode is not performed every time the cleaning mode is performed, so ozone water can be passed through at an optimal frequency, which reduces bacterial growth in the filtration material 19 while contributing to a longer lifespan of the filtration material 19 and a reduced replacement frequency.

[0071] (Embodiment 2) Water purifier 1b according to embodiment 2 of the present invention differs from embodiment 1 in that it changes the timing of executing the cleaning mode based on the value of a predetermined element. Other configurations are the same as those of water purifier 1 according to embodiment 1. Below, we will omit repetitive explanations of content already explained in embodiment 1, and will mainly explain the differences from embodiment 1. Specifically, the basic device configuration of water purifier 1b is the same as the configuration described in embodiment 1, but the configuration and processing of the control unit are different, and these differences will be explained.

[0072] The control unit 3x of the water purifier 1b will be described with reference to FIG.

[0073] The water purifier 1b includes a control unit 3x. The control unit 3x controls switching of the flow path of the water to be treated that flows through the water purifier 1b during each of the filtration mode, the water to be treated cleaning mode, and the ozone water cleaning mode. In addition to the memory unit 3b, the object to be treated comparison unit 3c, the determination unit 3d, the count count unit 3e, and the cleaning execution unit 3f of the control unit 3 in the first embodiment, the control unit 3x further includes a predetermined element identification unit 3g, a predetermined element memory unit 3h, a predetermined element comparison unit 3i, and a count change unit 3n.

[0074] The predetermined element specifying unit 3g specifies the value of a predetermined element of the water to be treated. It is appropriate to set a factor that affects bacterial growth within the filtration medium 19 as the predetermined element, such as water temperature. Methods for specifying the value of the predetermined element include, for example, a method in which a measuring unit is provided to measure the predetermined element and the element is measured automatically, a method in which an input unit is provided to input the value of the predetermined element and the user manually inputs the value, and a method in which information is obtained from a server or the like via a network. Furthermore, for example, if the predetermined element is water temperature, a specifying method may be set according to the required predetermined element, such as a method in which the predetermined element is estimated from the ambient air temperature.

[0075] The predetermined element storage unit 3h stores the reference value of the predetermined element as the element reference value. For example, if water temperature is selected as the predetermined element, it is preferable to set the element reference value to 20°C to 30°C, which is a temperature at which bacteria easily grow.

[0076] The predetermined element comparison unit 3i compares the value of the predetermined element identified by the predetermined element identification unit 3g with the element reference value stored in the predetermined element storage unit 3h, and transmits the comparison result to the number of times change unit 3n.

[0077] The count change unit 3n sets a first predetermined number or a second predetermined number to be used instead of the predetermined number based on the comparison result of the predetermined element comparison unit 3i and the predetermined number. Specifically, when water temperature is selected as the predetermined element, if the water temperature is higher than the element reference value, the count change unit 3n sets the first predetermined number to a number less than the predetermined number. On the other hand, if the water temperature is lower than the element reference value, the count change unit 3n sets the second predetermined number to a number greater than the predetermined number. Information on the first predetermined number or the second predetermined number is sent to the count measurement unit 3e, and the ozone water cleaning mode is executed when the count measured by the count measurement unit 3e reaches the first predetermined number or the second predetermined number. The first predetermined number is set within a range that does not result in 0.

[0078] The above is the configuration of the water purifier 1b.

[0079] Next, the operation of the water purifier 1b will be described.

[0080] The filtration mode and cleaning mode of the water purifier 1b will be described with reference to Fig. 8. Fig. 8 is a flowchart showing the operation of the water purifier 1b according to the second embodiment.

[0081] First, when the water purifier 1 is started, the filtration mode is initiated (step S201).

[0082] When the filtration mode is executed, the concentration measuring unit 20 measures the amount of purified water produced by the filtration unit 10. The concentration of the substance to be treated in the purified water is measured (step S202). The measured concentration information of the substance to be treated is sent to the substance to be treated comparison unit 3c.

[0083] The object comparison unit 3c compares the object concentration information received from the concentration measurement unit with the reference value of the object concentration stored in the memory unit 3b (step S203). If the comparison result shows that the object concentration is less than the reference value, the filtration mode continues (NO in step S203). On the other hand, if the object concentration is equal to or greater than the reference value (YES in step S203), the determination unit 3d determines that the filtering medium 19 needs to be cleaned (step S204).

[0084] The counting unit 3e counts the number of times that it has been determined that the cleaning is necessary.

[0085] Here, the predetermined element specifying unit 3g specifies the value of a predetermined element of the water to be treated (step S211). As the predetermined element, it is appropriate to set a factor that affects bacterial growth in the filtration medium 19, such as water temperature.

[0086] The predetermined element storage unit 3h stores the reference value of the predetermined element as the element reference value. For example, if water temperature is selected as the predetermined element, it is preferable to set the element reference value to 20°C to 30°C, which is a temperature at which bacteria easily grow.

[0087] The predetermined element comparison unit 3i compares the value of the predetermined element identified by the predetermined element identification unit 3g with the element reference value stored in the predetermined element storage unit 3h (step S212). The comparison result is sent to the number of times change unit 3n.

[0088] The count change unit 3n sets a first predetermined number of times or a second predetermined number of times to be used instead of the predetermined number of times based on the comparison result of the predetermined element comparison unit 3i and the predetermined number of times (step S213). Specifically, when water temperature is selected as the predetermined element, if the water temperature is higher than the element reference value, the count change unit 3n sets a number of times less than the predetermined number of times as the first predetermined number of times. On the other hand, if the water temperature is lower than the element reference value, the count change unit 3n sets a number of times greater than the predetermined number of times as the second predetermined number of times. Information on the identified first predetermined number of times or second predetermined number of times is transmitted to the count measurement unit 3e. The first predetermined number of times is set within a range in which the number does not become 0.

[0089] If the count counted by the count counting unit 3e is less than the specified first or second predetermined count (NO in step S205), the cleaning execution unit 3f ends the filtration mode (step S207a) and executes the untreated water cleaning mode (step S208a). If the execution time of the untreated water cleaning mode is less than a certain time (e.g., 10 minutes) (NO in step S209a), the untreated water cleaning mode is continued. On the other hand, if the execution time of the untreated water cleaning mode is equal to or longer than the certain time (YES in step S209a), the execution of the cleaning mode is ended and the filtration mode is executed or the system enters a standby state where the execution of the filtration mode is awaited.

[0090] On the other hand, if the count counted by the count counting unit 3e is equal to or greater than the specified first or second predetermined count (YES in step S205), the count counted by the count counting unit 3e for determining that the cleaning is required is reset (step S206).Then, the cleaning execution unit 3f ends the filtration mode (step S207b) and executes the ozone water cleaning mode (step S208b).

[0091] If the execution time of the ozone water cleaning mode is less than a certain time (for example, 2 minutes) (NO in step S209b), the ozone water cleaning mode continues to be executed. On the other hand, if the execution time of the ozone water cleaning mode is equal to or longer than a certain time (YES in step S209b), the execution of the cleaning mode is terminated, and the filtration mode is executed or the system enters a standby state waiting for the execution of the filtration mode. Note that the ozone water cleaning mode is executed by supplying ozone water to the filtration unit 10 during the execution of the ozone water cleaning mode. The total amount of water passing through the filter medium 19 is set to be equal to or greater than the volume of the filter medium 19 .

[0092] In this way, the water purifier 1b repeatedly executes the filtration mode, the untreated water cleaning mode, and the ozone water cleaning mode. In other words, the generation of purified water by the filtration unit 10 and the regeneration of the filtration unit 10 are repeatedly executed.

[0093] As described above, the water purifier 1b according to this embodiment can provide the following effects.

[0094] (3) The water purification device 1b is provided with a predetermined element identification unit 3g that identifies the value of a predetermined element of the water to be treated, and the control unit 3x is provided with a predetermined element memory unit 3h that stores the reference value of the predetermined element as the element reference value, and a predetermined element comparison unit 3i that compares the value of the identified predetermined element with the element reference value, and changes the timing of executing the cleaning mode depending on the comparison result between the value of the predetermined element and the element reference value when the filtration mode is executed.

[0095] With this configuration, the frequency of the ozone water cleaning mode can be changed depending on a specified predetermined factor, such as water temperature. Therefore, when the environment is favorable for bacterial growth on the filtration material 19, ozone water is used frequently to disinfect the filtration material 19. Otherwise, the frequency of ozone water flow can be reduced to prevent deterioration of the filtration material 19. As a specific example, if the specified factor in the water purifier 1 is the water temperature of the water being treated and the water temperature is greater than a reference factor, the ozone water cleaning mode is executed when a first predetermined number of times is reached, which is less than the predetermined number of times. As a result, for example, bacterial growth is active during high water temperatures, such as summer, but the operating method described above can increase the frequency of ozone cleaning and prevent bacterial growth. Furthermore, if the specified factor in the water purifier 1 is the water temperature of the water being treated and the water temperature is less than the reference factor, the ozone water cleaning mode is not executed even when the predetermined number of times is reached, but is executed when a second predetermined number of times is reached, which is greater than the predetermined number of times. As a result, bacterial growth is slower during low water temperatures, such as winter, so the frequency of ozone cleaning can be reduced and deterioration of the filtration material 19 can be prevented.

[0096] (Embodiment 3) A water purifier 1c according to a third embodiment of the present invention differs from the first embodiment in that it executes an ozone water cleaning mode before executing a filtration mode based on the amount of water passing through per predetermined period. Other configurations are the same as those of the water purifier 1 according to the first embodiment. Below, we will omit redundant explanations of the content already explained in the first embodiment, and will mainly explain the differences from the first embodiment. Specifically, the basic configuration of the water purifier 1c is the same as that described in the first embodiment, but the configuration and processing of the control unit are different, and these differences will be explained.

[0097] The control unit 3y of the water purifier 1c will be described with reference to FIG.

[0098] The water purifier 1c includes a control unit 3y. The control unit 3y controls switching of the flow path of the water to be treated circulating within the water purifier 1c during each of the filtration mode, the water-to-be-treated cleaning mode, and the ozone water cleaning mode. In addition to the memory unit 3b, the object-to-be-treated comparison unit 3c, the determination unit 3d, the count unit 3e, and the cleaning execution unit 3f of the control unit 3 in the first embodiment, the control unit 3y further includes a water volume measurement unit 3j, a water flow rate calculation unit 3p, a water flow rate memory unit 3k, and a water flow rate comparison unit 3m.

[0099] The water volume measuring unit 3j measures the amount of water to be treated passing through the filtration unit 10. Information relating to the measured amount of passing water is sent to the water volume integrating unit 3p.

[0100] The water flow rate integrating unit 3p calculates the water flow rate measured by the water flow rate measuring unit 3j over a predetermined period (for example, several days to one week). The total amount of water flow is calculated for each period (hours).

[0101] The water flow rate storage unit 3k stores the reference value of the water flow rate for a predetermined period of time as the water flow rate reference value. This predetermined period is the same as the predetermined period in the water flow rate integrating unit 3p. The water flow rate reference value is preferably a water amount that does not replace all of the water accumulated in the water purifier 1c, and for example, for a home water purifier, it is approximately 0 L to 50 L.

[0102] The water flow rate comparison unit 3m compares the accumulated water flow rate calculated by the water flow rate accumulating unit 3p with the water flow reference value stored in the water flow rate storage unit 3k.

[0103] The above is the configuration of the water purifier 1c.

[0104] Next, the operation of the water purifier 1c will be described.

[0105] The filtration mode and cleaning mode of the water purifier 1c will be described with reference to Fig. 10. Fig. 10 is a flowchart showing the operation of the water purifier 1c according to the third embodiment.

[0106] First, when the water purifier 1 is started, the water volume measuring unit 3j measures the amount of water to be treated flowing through the filtration unit 10 (step S311).

[0107] The measured water flow rate is integrated by the water flow rate integration unit 3p, and the water flow rate for a predetermined period is calculated as the integrated water flow rate (step S312).

[0108] The calculated cumulative water flow rate is compared by the water flow rate comparison unit 3m with a water flow reference value for a predetermined period stored in the water flow rate storage unit 3k (step S313). If the cumulative water flow rate for the predetermined period is equal to or greater than the water flow reference value (YES in step S313), the water purifier 1c enters a standby state in which the filtration mode can be executed (step S316).

[0109] On the other hand, if the cumulative amount of water passing per predetermined period is less than the water passing reference value (NO in step S313), the cleaning execution unit 3f starts the ozone water cleaning mode (step S314).

[0110] If the execution time of the ozone water cleaning mode is less than a certain time (e.g., 2 minutes) (NO in step S315), the ozone water cleaning mode continues to be executed. On the other hand, if the execution time of the ozone water cleaning mode is equal to or longer than a certain time (YES in step S315), the execution of the cleaning mode ends, and the water purifier 1c enters a standby state in which the filtration mode can be executed (step S316). Thereafter, the filtration mode is started as necessary. The flow after the start of the filtration mode is the same as the flow shown in embodiment 1, and therefore a description thereof will be omitted.

[0111] As described above, in the water purifier 1c, the ozone water cleaning mode is executed before the filtration mode is started, depending on the amount of water passing through per predetermined period.

[0112] As described above, the water purifier 1c according to this embodiment can provide the following effects.

[0113] (4) The water purifier 1c is equipped with a water volume measuring unit 3j that measures the amount of water passing through the filtration unit 10. The control unit 3y is equipped with a water volume memory unit 3k that stores the reference value of the amount of water passing through in a predetermined period as the reference water volume, and a water volume comparison unit 3m that compares the measured amount of water passing through with the reference water volume. If the amount of water passing through in a predetermined period is less than the reference water volume, the ozone water cleaning mode is executed before the filtration mode is executed. If the water purifier 1c has not been used for a predetermined period and water has accumulated inside the device, the accumulated water may cause bacteria to grow in the filtration material 19. However, this With this configuration, if the water purifier 1c has not been used for a predetermined period of time, the ozone water cleaning mode is executed before the filtration mode is executed, thereby sterilizing the filtration material 19 with ozone. This reduces the possibility that the purified water will contain grown bacteria, and clean purified water can be obtained.

[0114] Furthermore, in many cases, during operation of the water purifier 1, the total amount of untreated water or cleaning water passing through the filtration unit 10 in the untreated water cleaning mode and the ozone water cleaning mode is less than the amount of untreated water passing through the filtration unit 10 in the filtration mode. In other words, the amount of water passing through the filtration unit 10 when the filtration material 19 is being regenerated is less than the amount of water passing through the filtration unit 10 when purified water is produced. However, depending on the usage environment of the water purifier 1, the amount of water passing through the filtration unit 10 in the filtration mode may be equal to or greater than the total amount of water passing through the filtration unit 10 in the untreated water cleaning mode and the ozone water cleaning mode.

[0115] The present invention has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component or each treatment process, and that such modifications are also within the scope of the present invention.

[0116] In the second embodiment, water temperature is used as the predetermined element, but this is not limiting. For example, the amount of water flowing into the filtration unit 10 (water flow rate) can be used as the predetermined element. In this case, a water meter capable of measuring the amount of water flowing through the filtration unit 10 is provided. For example, 1000 L, the average daily amount used in a typical household, is set as the element reference value, and the first or second predetermined number of times is set based on this. Specifically, if the amount of water flowing into the filtration unit 10 per reference time is greater than the element reference value, the first predetermined number of times is set, and the ozone water cleaning mode is performed fewer times than the predetermined number of times when it is determined that a cleaning is required. In a water purifier, the greater the amount of water flow rate, the greater the amount of material captured by the filtration material 19, which may promote the growth of bacteria that use the material as a nutrient source. However, by using the above method, the ozone water cleaning mode can be performed more frequently than usual when the amount of water flowing in is large, thereby suppressing bacterial growth due to the accumulation of material that could serve as nutrients for bacteria. On the other hand, if the amount of inflowing water per reference time is less than the element reference value, a second predetermined number of times is set, and the ozone water cleaning mode is performed a number of times greater than the predetermined number of times when it is determined that cleaning is required. In a water purifier, when the amount of inflowing water is low, the amount of material adhering to the filtration material 19 is small, slowing the growth of bacteria that use the material as a nutrient source. By using the above operating method, the number of times of the ozone water cleaning mode can be reduced in such cases, thereby suppressing deterioration of the filtration material 19. Note that the actual values of the first predetermined number of times and the second predetermined number of times can be set to different values depending on whether the water temperature is used or the water flow rate is used. Note that the element reference value can also be set by measuring the frequency of use of the water purifier 1 and setting a certain frequency as the element reference value.

[0117] In the third embodiment, the water volume measuring unit 3j is configured within the control unit 3y, but this is not limiting, and for example, it may be provided outside the control unit 3 as a water meter. [Industrial Applicability]

[0118] The water purifier according to the present invention can be applied to a water purifier installed at the point of use (POU) or a water purifier installed at the entrance of a building (POE) or the like. [Explanation of symbols]

[0119] 1. Water purification equipment 1b Water purification equipment 1c Water purification device 2. Water piping 3. Control Unit 3x control unit 3y control section 3b Storage section 3c Processed object comparison section 3d judgment section 3e Number measurement unit 3F Cleaning Execution Department 3g Predetermined element identification part 3h Predetermined element storage section 3i Predetermined element comparison section 3j Water measurement section 3k water flow storage unit 3m water flow comparison section 3n Number of times change part 3p Water flow rate accumulator 5 Upstream switching valve 7 Ozone generator 9. Ozone water generation unit 10 Filtration section 11. Switching valve 13 One end opening 15 Water Pipe 17 Other end opening 19 Filter media 20 Concentration measurement section 21 Inlet 22 Inflow pipe 23a First water pipe 23b Second water pipe 23c Third water pipe 24 Constant flow valve 25 Three-way valve 26 Purified water discharge pipe 27 Clean water outlet 28 Backwash discharge pipe 29 Backwash outlet A Branching Point B Junction

Claims

1. a filtering section that removes the material to be treated from the water to be treated using a filtering material to produce purified water; A concentration measuring unit for measuring the concentration of the substance to be treated in the purified water; a control unit that controls execution of a filtration mode in which the purified water is produced from the water to be treated and a cleaning mode in which the filtration material is cleaned; The control unit a storage unit that stores the reference value of the concentration of the object to be treated; a processing object comparison unit that compares the measured processing object concentration with the reference value; a determination unit that determines that the filtering material is in a cleaning-needed state when the concentration of the target substance in the purified water generated in the filtration mode is equal to or greater than the reference value; a cleaning execution unit that executes the cleaning mode when the determination unit determines that the water needs to be cleaned.

2. an ozone generating unit that generates ozone gas by electrolysis of water; an ozone water generating unit that mixes the ozone gas with the water to be treated or the purified water to generate ozone water, The cleaning mode is a water-to-be-treated washing mode in which the water to be treated is fed to the filtration unit in a direction opposite to the water-to-be-treated water feeding direction in the filtration mode; an ozone water cleaning mode in which the ozone water is supplied to the filtration section, The control unit a frequency measuring unit that measures the number of times the cleaning-required state has been determined, The cleaning execution unit The water to be treated is washed in the washing mode until the washing-needed state is determined a predetermined number of times.

2. The water purifier according to claim 1, wherein the ozone water cleaning mode is executed when the cleaning-needed state is determined a predetermined number of times.

3. a predetermined element specifying unit that specifies the value of a predetermined element of the water to be treated, The control unit a predetermined element storage unit that stores the reference value of the predetermined element as an element reference value; a predetermined element comparison unit that compares the value of the specified predetermined element with the element reference value, 3. The water purifier according to claim 2, wherein the timing of executing the cleaning mode is changed depending on a result of comparison between the value of the predetermined element during execution of the filtration mode and the element reference value.

4. the predetermined element is the temperature of the water to be treated, 4. The water purifier according to claim 3, wherein when the water temperature is higher than the element reference value, the ozone water cleaning mode is executed when the number of times reaches a first predetermined number, which is less than the predetermined number of times.

5. the predetermined element is the temperature of the water to be treated, The water purifier of claim 3, wherein when the water temperature is lower than the element reference value, the ozone water cleaning mode is not executed even when the predetermined number of times is reached, and the ozone water cleaning mode is executed when a second predetermined number of times, which is greater than the predetermined number of times, is reached.

6. the predetermined element is the inflow amount of the water to be treated, When the amount of inflow water per reference time is greater than the element reference value, the ozone water cleaning mode is executed when the number of times reaches a first predetermined number, which is less than the predetermined number of times. The water purifier according to claim 3.

7. the predetermined element is the inflow amount of the water to be treated, The water purifier of claim 3, wherein when the amount of inflow water per reference time is smaller than the element reference value, the ozone water cleaning mode is not executed even when the predetermined number of times is reached, and the ozone water cleaning mode is executed when a second predetermined number of times, which is greater than the predetermined number of times, is reached.

8. A water volume measuring unit is provided to measure the amount of water passing through the filtration unit, The control unit a water flow rate storage unit that stores the reference value of the water flow rate for a predetermined period as a water flow reference value; a water flow rate comparison unit that compares the measured water flow rate with the water flow reference value, 3. The water purifier according to claim 2, wherein the ozone water cleaning mode is executed before the filtration mode is executed when the amount of water passing per predetermined period is less than the reference water passing value.

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